Stainless Works SBF Wide Rectangular Port Header Adapter 304SS Exhaust Flanges 1-7/8in-2in PrimariesSmall Block Ford big tube wide rectangular shaped port header adapter exhaust flanges. These flanges come as a pair and are designed for 2" horizontal centerline bolt pattern SBF heads, machine work included. Includes (8) countersunk holes for bolting 3 8" diameter flat head bolts to head and (8) 3 8" 16 tapped holes to locate SBF flanges with larger port sizes for 1 7 8" or 2" diameter primaries. SBF header flanges not included, laser cut from heavy